This invention relates generally to the field of fan duct burning and ram burning engines, and more particular to annular fan duct burners and ram burners which must perform effectively over a wide range of operation condition. The usual fan duct burning and ram burning engine has flameholding characteristics for a given operating condition determined by a large degree by the dynamics at the flameholder plane, which are in turn determined by flameholder plane geometry. The geometry at the flameholder plane is normally fixed and for this reason the operating range of the fan duct burner and ram burner is limited to a narrow band around the design point of the burner.